The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Current coaxial to waveguide transition modules require a quarter wavelength back short between the conductive elements and a ground plane. For example, for operations at 15 GHz using a construction material with a relative dielectric of 2.2 and a circular waveguide diameter of 0.340 inch, the quarter wavelength is approximately 0.350 inch thick. Put differently, the quarter wavelength back short will have a height of about 0.350 inch. When this transition module is fabricated into a printed wiring board that also contains clock, data, voltage, ground planes and multiple stripline layers (as required for multiple polarizations or frequencies), the final stackup height of the overall assembly can easily exceed about 0.450 inch in height. Such a height is undesirable for a number of applications, and particularly phased array antenna applications, where the compactness of the module is of the utmost importance.
Existing solutions typically require construction of two separate wiring boards, one containing the quarter wavelength back short and one containing the additional circuits. The separate wiring boards are then joined using an epoxy bond process. As will be appreciated, the requirement of having to join the two assemblies with epoxy adds to the manufacturing complexity and cost of producing a waveguide transition module. The resulting module may also be undesirably thick.